Virtual Body: Fundamental Concepts: 2
When your physical form is not moving for an extended period of time, you start
By muscle atrophy in this context, we really mean disuse atrophy. Disuse atrophy occurs when the muscles are not being used for extended period of time. The body starts to recycle muscle material that has not been used hard, after a period of months. The muscle mass decreases, and can even start to waste away to the point the muscles can no longer be properly utilised, as in the case of the bed ridden.
It does not take VR to show signs of this, if you have a sedentary job, or a limiting disability, you experience muscle loss, as the limb is not used to its full effectiveness continually.
The effects are reversible with vigorous exercise, or electrical stimulation of the muscles, forcing them to expand and contract.
It is clear that for any long-term immersion VR system, a method should be in place to stimulate the muscles of the physical body, to prevent atrophy.
Pressure Sores / bedsores
If a single posture is maintained for an overly long period of time - as happens with wheelchair users - then pressure ulcers or pressure sores will develop on the posterior region. If untreated, these can be fatal.
Pressure sores can lead to severe medical complications, include bone and blood infections, infectious arthritis, holes below the wound that burrow into bone or deeper tissues, and scar carcinoma, a form of cancer that develops in scar tissue.
This pressure temporarily cuts off the skin's blood supply. This injures skin cells and can cause them to die. Unless the pressures are relieved and blood flows to the skin again, the skin soon begins to show signs of injury. At first, there may be only a patch of redness. If this red patch is not protected from additional pressure, the redness can form blisters or open sores. If the pressure is still not abated, damage may extend through the skin and create a deep crater that exposes muscle or bone.
Muscle is even more prone to severe injury from cross-pressure (pressure in directions other than the line of the muscle, where it cannot contract) than skin. A mild injury to the skin may cover a deeper, more pronounced injury to muscle.
Proper support for the body is essential if a position is to be maintained for any prolonged period of time. Since taking a break every 15 minutes is nigh on impossible, and definitely impractical when fully immersed in a virtual environment, alternate measures must be sought. There must be no pressure points or distortions otherwise tensions and strains in the bone structure and muscles will keep the whole nervous system subconsciously active. This will result in constant repositioning and increased fatigue, stress and irritability. A problem all too familiar to intensive gamers, and computer programmers.
To prevent pressure sore formation, either the whole body must be supported - ideally in liquid such as an immersion tank - or systems must be in place to move pressure locations periodically - a reclining interface with pads that raise and lower.
Malnourishment occurs when your diet does not meet the quality required in terms of minimum daily requirements for proteins, vitamins, minerals and other nutrients. In short, when you don't recieve the food your body requires for survival.
When you are hooked up to an immersive environment for many hours at a stretch; possibly even days or weeks, the provision of food becomes an issue. The physical body needs to be monitored for signs of deteriorating healh, and food and drink added in, likely via feeding tube, or drip at regular intervals.
The above quote from a novel covering the subject, is essentially accurate. In order to prevent malnourishment, the simulation rig itself, must provide feeding.
Endless pumping of food into the body will not work. Eventually it must come out. As well as feeding food in, it must deal with continual extraction of waste products, in one form or another, via additional tubes.
Emergency situations are varied, and will be covered in more depth in Fundamental Concepts: 3. However, they are basically any event in which there is a sudden real need to disconnect the physical body from interface hardware, and reconnect the mind to control of it. Any such disconnect is going to be disoeientating, and for those whose virtual body is far more functional, even traumatic.
There has to be functionality in place, to quickly yet without sudden disconnects, warn the mind that it is being returned to the physical body - perhaps by a gradualt deresolution of senses, and the ability to do so even if it has already been disconnected from the wider simulation, to move the physical unit - it must be able to keep a memory of sensory stimulai, for any change over.